How do we decide whether to call a shirt a ワイシャツ or 背広 ? What's the difference in nuance between the two terms?
Side question: EDICT claims that a ホワイトシャツ is a white business shirt but even if it's a gray or black (or what-have-you) colored business shirt, we can still call it a ホワイトシャツ or ワイシャツ right?